1 /* 2 * Copyright 2011 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef SkClampRange_DEFINED 9 #define SkClampRange_DEFINED 10 11 #include "SkFixed.h" 12 #include "SkScalar.h" 13 14 #define SkGradFixed SkFixed3232 15 16 // We want the largest 32.32 value representable as a float. (float)0x7FFFFFFF 17 // becomes too big, due to limited mantissa on the float and its rounding rules, so 18 // we have to manually compute the next smaller value (aka nextafter). 19 20 // #define SkGradFixedMaxScalar nextafterf(SkFixed3232ToFloat(SkFixed3232Max), 0) 21 // #define SkGradFixedMinScalar nextafterf(SkFixed3232ToFloat(SkFixed3232Min), 0) 22 #define SkGradFixedMaxScalar ( 2147483520.0f) 23 #define SkGradFixedMinScalar (-2147483520.0f) 24 #define SkScalarPinToGradFixed(x) SkScalarToFixed3232(SkTPin(x, \ 25 SkGradFixedMinScalar,\ 26 SkGradFixedMaxScalar)) 27 #define SkFixedToGradFixed(x) SkFixedToFixed3232(x) 28 #define SkGradFixedToFixed(x) (SkFixed)((x) >> 16) 29 #define kFracMax_SkGradFixed 0xFFFFFFFFLL 30 31 /** 32 * Iteration fixed fx by dx, clamping as you go to [0..kFracMax_SkGradFixed], this class 33 * computes the (up to) 3 spans there are: 34 * 35 * range0: use constant value V0 36 * range1: iterate as usual fx += dx 37 * range2: use constant value V1 38 */ 39 struct SkClampRange { 40 int fCount0; // count for fV0 41 int fCount1; // count for interpolating (fV0...fV1) 42 int fCount2; // count for fV1 43 SkGradFixed fFx1; // initial fx value for the fCount1 range. 44 // only valid if fCount1 > 0 45 int fV0, fV1; 46 47 void init(SkGradFixed fx, SkGradFixed dx, int count, int v0, int v1); 48 validateSkClampRange49 void validate(int count) const { 50 #ifdef SK_DEBUG 51 SkASSERT(fCount0 >= 0); 52 SkASSERT(fCount1 >= 0); 53 SkASSERT(fCount2 >= 0); 54 SkASSERT(fCount0 + fCount1 + fCount2 == count); 55 #endif 56 } 57 58 private: 59 void initFor1(SkGradFixed fx); 60 }; 61 62 #endif 63